I’m confused about the rocker arm differences on the O-360-A4K parallel valve cylinders because I know about the extreme heat that the exhaust valves endure. Please share: Continue Reading →

I have a Lycoming O-360-A3A in my Cherokee. According to the Type Certificate Data Sheets (TCDS), this engine is similar to an -A1A, except without provisions for a constant speed prop. Nevertheless, it is equipped with a hollow crankshaft, and... Continue Reading →

I own a 1974 Grumman AA-5, SN550. Last winter I had the engine (O-320) rebuilt. I have a question about EGTs. Continue Reading →

I own a Cessna R-182 that has a Lycoming O-540 J3C5D engine. It seems like a great engine and runs well. I have a concern about the “”dual-pack”" type magnetos that run off a common gear. Yesterday, another pilot told... Continue Reading →

After my Nov. 3 column, “”Why are there increased levels of copper in my oil?”" was published, I received some valuable advice from industry experts on the subject. Continue Reading →

I am having a hard time finding any usefulness in your column. People ask specific questions and you tell them to look it up. As a reader, I would like to see some sort of expert answer to their questions.... Continue Reading →

Recent oil analyses seem to be showing increased levels of copper coming from my XP-360. Could you help with a diagnosis? Continue Reading →

Can you give me an idea of what STCs are available to convert an O-320-E3D from 150 to 160 hp? Continue Reading →

I often hear from U.S. mechanics that in their opinion the only way to really test a mag is to do it while flying. They say that’s because you can really get the highest rpm, say 2,550, and then do... Continue Reading →

My friend and I were discussing why many Lycoming engines were built without oil filters, just oil screens. He guessed it was because in the beginning they just didn’t have oil filter technology, and once certified, the engine design is... Continue Reading →